Air conditioning apparatus heat pump system, air conditioning apparatus and defrosting control method thereof

Abstract

The application provides an air conditioner heat pump system, an air conditioner and a defrosting control method thereof. The heat pump system comprises a main heat exchanger, a water inlet pipe and a water outlet pipe arranged on one side of the main heat exchanger, a water circulating pump arranged on the water inlet pipe, a liquid accumulator, a suction main pipe and at least two sets of heat exchange units. The heat exchange unit comprises an electronic expansion valve, an air heat exchanger, an electromagnetic three-way valve, a working compressor, a working check valve and a heating electromagnetic valve. The other side of the main heat exchanger is sequentially connected with the liquid accumulator, the electronic expansion valve, the air heat exchanger, the electromagnetic three-way valve, the suction main pipe, the working compressor, the working check valve and the heating electromagnetic valve through pipelines to form a heating circuit. The electronic expansion valve is provided with a defrosting check valve in parallel. The third end of the electromagnetic three-way valve is communicated with the pipeline between the working check valve and the heating electromagnetic valve. The suction main pipe, the working compressor, the working check valve, the electromagnetic three-way valve, the air heat exchanger, the defrosting check valve and the liquid accumulator are connected through pipelines to form a defrosting branch circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of air-conditioning equipment, and in particular to an air-conditioning equipment heat pump system, air-conditioning equipment and a defrosting control method thereof. Background Art

[0002] During winter heating operation, the outdoor air heat exchanger acts as the evaporator. Due to the low ambient temperature, the surface temperature of the outdoor air heat exchanger also drops. When the surface temperature of the outdoor air heat exchanger is lower than the dew point of the surrounding air and below 0°C, the moisture in the cooled air will precipitate as the outdoor air flows through the outdoor heat exchanger, forming a frost layer on the outdoor air heat exchanger. The presence of the frost layer reduces the heat transfer coefficient of the air heat exchanger surface and increases wind resistance due to the reduced gap between the copper tubes. Both of these factors reduce the heat transfer efficiency of the air heat exchanger, forcing the air conditioner to activate the defrost mode. Especially in southern regions with high humidity, winter heating outdoor units frequently frost. Due to design flaws in the defrost mechanism, the defrost time is long, resulting in the system's overall inability to meet heating needs. Currently, air conditioners on the market usually use a four-way valve to switch the air conditioning mode to cooling mode for defrosting. The outdoor air heat exchanger acts as a condenser, the indoor heating stops, and heat is absorbed from the indoor side. The defrost cycle is generally 7-10 minutes, which causes large fluctuations in indoor temperature and greatly reduces indoor comfort. At the same time, since the high-pressure side is completely in the low-temperature domain of the frosted air heat exchanger, effective high pressure cannot be formed. Therefore, the refrigerant circulation flow is extremely low, the heat generated is extremely small, and the defrost time is greatly prolonged.

[0003] Therefore, there is an urgent need in the art for an air-conditioning equipment heat pump system, air-conditioning equipment and a defrost control method thereof.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] An object of the present invention is to provide an air-conditioning equipment heat pump system, air-conditioning equipment and a defrost control method thereof, so as to solve at least one of the above-mentioned technical problems.

[0006] Specifically, the application provides an air conditioner heat pump system, which comprises a main heat exchanger, a water inlet pipe and a water outlet pipe are arranged on one side of the main heat exchanger, a water circulating pump is arranged on the water inlet pipe, the air conditioner heat pump system further comprises a liquid accumulator, a suction main pipe and at least two groups of heat exchange units, the heat exchange unit comprises an electronic expansion valve, an air heat exchanger, an electromagnetic three-way valve, a working compressor, a working check valve and a heating electromagnetic valve, the other side of the main heat exchanger is sequentially connected with the liquid accumulator, the electronic expansion valve, the air heat exchanger, the electromagnetic three-way valve, the suction main pipe, the working compressor, the working check valve and the heating electromagnetic valve through pipelines to form a heating circuit, the electronic expansion valve is provided with a defrosting check valve in parallel, the third end of the electromagnetic three-way valve is communicated with the pipeline between the working check valve and the heating electromagnetic valve, and the suction main pipe, the working compressor, the working check valve, the electromagnetic three-way valve, the air heat exchanger, the defrosting check valve and the liquid accumulator are connected through pipelines to form a defrosting branch.

[0007] When the heating circuit is used, the electronic expansion valve, the heating electromagnetic valve and the working compressor are opened, and the electromagnetic three-way valve communicates the air heat exchanger with the suction main pipe; when the defrosting branch is used, the electronic expansion valve and the heating electromagnetic valve are closed, and in the defrosting branch, the working compressor extracts gaseous refrigerant in the suction main pipe, and the gaseous refrigerant is condensed and liquefied through the air heat exchanger and flows into the liquid accumulator.

[0008] Adopting the above scheme, in the heating circuit, the working compressor pushes the flow of the refrigerant in the pipeline, the liquid refrigerant in the air heat exchanger evaporates and absorbs heat, the gaseous refrigerant in the main heat exchanger condenses and releases heat, and reversely exchanges heat with the water flow on the other side, so as to transfer heat to the water in the outlet pipe, and other heat exchangers can be connected between the outlet pipe and the water pipe, and indoor heating is realized by using the other heat exchangers; the gaseous refrigerant in the suction manifold is extracted by the defrosting branch, so that it releases heat and condenses in the air heat exchanger, thereby realizing defrosting, and the heat exchange unit has at least two groups, which can ensure that the heating circuit is running at the same time when the defrosting branch is opened, so as to defrost the air heat exchanger frosted outdoors by using the heat absorbed outdoors under the condition of uninterrupted heating, and the optimal energy efficiency of the working compressor is realized by using the precise temperature control algorithm PID and the cooperation of the electronic expansion valve and the working compressor, so that the system runs in a non-full load working condition for a long time. In addition to increasing the suction pressure to the extreme and maximizing the energy efficiency of the working compressor, the evaporation area of multiple air heat exchangers can also be ensured, the minimum air heat exchange temperature difference of the air heat exchanger is realized, the surface temperature of the air heat exchanger is maintained at a high level, the defrosting speed is effectively reduced, the defrosting frequency is reduced, and even when the surface temperature is higher than the ambient dew point temperature, the defrosting phenomenon can be avoided; the gaseous refrigerant is collected in the suction manifold, the defrosting branch extracts the heat of the suction manifold, and the heat of the user water circulation system has no significant effect on the temperature control of the user side, thereby ensuring normal heating work; the refrigerant in the suction manifold is extracted and compressed by the working compressor of at least one heating circuit, and the system can also run normally when one of the working compressors fails, thereby ensuring that the refrigerant passes through all the air heat exchangers, ensuring the maximum evaporation area and the efficiency ratio, and improving the fault tolerance rate; the working check valve prevents the gaseous refrigerant from flowing reversely into the working compressor and causing damage to the working compressor.

[0009] Preferably, the main heat exchanger can be a plate heat exchanger, a shell-and-tube heat exchanger or a double-pipe heat exchanger.

[0010] Further, the working compressor is at least one variable capacity compressor.

[0011] Preferably, the working compressor is at least one digital scroll compressor.

[0012] Adopting the above scheme, the variable capacity compressor can adopt frequency conversion technology, a multi-stage control system, digital scroll technology, etc., to realize accurate adjustment of the overall heating / cooling capacity.

[0013] Further, the auxiliary compressor and the auxiliary check valve are further connected between the suction manifold and the main heat exchanger, and the auxiliary compressor is a variable capacity compressor.

[0014] With the above solution, the auxiliary one-way valve prevents the gaseous refrigerant from flowing back into the auxiliary compressor, and the auxiliary compressor uses variable capacity technology to adjust the total heating amount.

[0015] Preferably, the heat exchange units are arranged in four groups.

[0016] With the above solution, when one defrost branch is selected for defrosting, the other three heating circuits can ensure a better heating effect and the compressor has better efficiency.

[0017] Furthermore, a refrigeration one-way valve is connected to the pipeline between the main heat exchanger and the liquid reservoir, the liquid reservoir is connected to the other end of the main heat exchanger through a pipeline, and a refrigeration expansion valve is provided in the pipeline, and a branch is formed between the refrigeration one-way valve and the pipeline of the main heat exchanger, the branch is connected to the intake main pipe, and a refrigeration solenoid valve is provided on the branch.

[0018] Among them, when the refrigeration solenoid valve and the electromagnetic three-way valve are opened, the heating solenoid valve and the electronic expansion valve are closed, and the main heat exchanger, the refrigeration solenoid valve, the air intake manifold, the working compressor, the working one-way valve, the electromagnetic three-way valve, the air heat exchanger, the defrost one-way valve, the liquid reservoir, and the refrigeration expansion valve are connected in sequence to form a refrigeration circuit, so that the refrigerant flows in the opposite direction and evaporates and absorbs heat in the main heat exchanger; the refrigeration one-way valve is used to prevent the refrigerant from flowing back to the main heat exchanger, the electromagnetic three-way valve connects the working one-way valve and the air heat exchanger, and the refrigeration expansion valve cooperates with the working compressor to adjust the cooling capacity.

[0019] By adopting the above scheme, the heat pump system of the air-conditioning equipment changes the flow direction of the refrigerant by switching the electromagnetic three-way valve, heating solenoid valve, electronic expansion valve, cooling expansion valve, and cooling solenoid valve, so that it can perform cooling while running the heating condition, achieving dual cooling and heating effects.

[0020] Furthermore, a heat exchange fan is provided opposite to the air heat exchanger.

[0021] By adopting the above solution, the heat exchange fan accelerates the air flow on the surface of the air heat exchanger, thereby improving the heat exchange rate.

[0022] Furthermore, the air-conditioning equipment heat pump system also includes a control system, which includes a main controller and a first temperature sensor, a second temperature sensor, a third temperature sensor and a first pressure sensor electrically connected thereto, the first temperature sensor being used to measure the water pipe temperature T01, the second temperature sensor being used to measure the air heat exchanger pipeline outlet temperature T21, the third temperature sensor being used to measure the air outlet side temperature Ts of the air heat exchanger surface, and the first pressure sensor being used to measure the intake main pipe pressure P10.

[0023] By adopting the above solution, the temperature and pressure parameters required in the heating circuit and the defrost circuit are obtained, which facilitates defrost control in the heating circuit.

[0024] Furthermore, the main controller is also electrically connected to a fourth temperature sensor, and the fourth temperature sensor is used to measure the outlet pipe temperature T20 of the main heat exchanger.

[0025] The above technical solution is adopted to facilitate the measurement of temperature data in the circuit and facilitate refrigeration control.

[0026] Furthermore, the main controller is also electrically connected to a fifth temperature sensor and a sixth temperature sensor, the fifth temperature sensor is used to measure the outdoor air temperature T0, and the sixth temperature sensor is used to measure the water outlet pipe temperature.

[0027] The above solution makes it easier to obtain the cooling or heating capacity obtained by the user side, so as to adjust the temperature more accurately and detect faults in time.

[0028] Furthermore, the main controller is also electrically connected to a seventh temperature sensor, a second pressure sensor, and a third pressure sensor. The seventh temperature sensor is used to measure the temperature of the intake manifold, the second pressure sensor is used to measure the exhaust pressure of the working compressor, and the third pressure sensor is used to measure the exhaust pressure of the auxiliary compressor.

[0029] The above solution makes it easy to obtain various data so as to better evaluate and control the performance of the compressor.

[0030] On the other hand, the present invention provides an air-conditioning device, which includes the air-conditioning device heat pump system as described above. Since the air-conditioning device heat pump system has the above technical effects, the air-conditioning device should also have corresponding technical effects.

[0031] The present invention provides a heating control method, comprising the following steps:

[0032] Connect the heating circuit and close other paths;

[0033] Obtain the water pipe temperature T01 and the user-set temperature Tset, calculate the temperature difference dT = T01 - Tset, and use the PID algorithm to calculate the output MV = PID (dT);

[0034] Calculate the number of compressors that need to be turned on and / or the load ratio based on the output MV;

[0035] The evaporation superheat of the air heat exchanger is controlled to be at a preset value by controlling the opening of the electronic expansion valve.

[0036] In the specific implementation process, the output volume MV is generally limited to the range of 5 to 100 (%). The number of compressors that need to be turned on can be converted according to the PID output volume MV. The compressors may include working compressors or working compressors and auxiliary compressors. For example, if 4 working compressors are included, all of which are fixed capacity and each compressor accounts for 25%, the output volume MV is 50%, which means that 2 working compressors are turned on. When variable capacity compressors are included, it can be refined to the loading ratio of the variable capacity compressors. For example, there are a total of 4 working compressors, three of which are fixed capacity and the other is variable capacity. The output volume When MV is 60%, two fixed-capacity compressors (25%*2) can be turned on, and then the variable-capacity compressor can be turned on 40% (25%*40%). The total output MV = 25%*2+25%*40% = 60%. For example, there are a total of 4 compressors, including 3 working compressors, all of which are fixed-capacity, and 1 auxiliary compressor, which is variable-capacity. When the output MV is 60%, two working compressors (25%*2) can be turned on, and then the auxiliary compressor can be turned on 40%. If the temperature deviation dT is less than -2°C, the heating operation will be stopped until the temperature deviation dT is greater than 2°C and then restarted.

[0037] By adopting the above solution, by adjusting the cooling capacity output appropriately rather than at its maximum, the evaporation temperature is made the highest within the working range, thereby obtaining the maximum energy efficiency ratio of the compressor, while at the same time achieving the highest surface temperature of the air heat exchanger and thus minimizing frost.

[0038] Furthermore, controlling the evaporation superheat of the air heat exchanger to a preset value by controlling the opening of the electronic expansion valve includes the following steps:

[0039] Receive the air heat exchanger pipeline outlet temperature T21 and the suction main pressure P10;

[0040] Calculate the evaporation superheat SH1 of the air heat exchanger = T21 – Te1, where Te1 is the saturation temperature corresponding to the suction main pressure P10;

[0041] If it is determined that the evaporation superheat SH1 exceeds the preset value, the electronic expansion valve opening V21 is increased and adjusted; if SH1 is lower than the preset value, the electronic expansion valve opening V21 is decreased and adjusted.

[0042] In the specific implementation process, Te1 can be obtained by looking up the table method. The preset value of SH1 is usually around 5°C. The electronic expansion valve opening V21 = V*(1+dV1), where V is the actual load of the current compressor, dV1 is the set adjustment amount, the initial value is 0, and it can vary within the range of ±50%. When SH1 is too high, dV1 is appropriately increased. When SH1 is too small, dV1 is appropriately reduced. The judgment period can be set to about 3 to 5 seconds, and the single adjustment amount of dV1 can be set to about 2%.

[0043] The present invention provides a refrigeration control method, comprising the following steps:

[0044] Connect the refrigeration circuit and close other pathways;

[0045] Receive the water pipe temperature T01 and the user set temperature Tset, calculate the temperature difference dT = T01 - Tset, and use the PID algorithm to calculate the output MV = PID (dT);

[0046] Calculate the number of compressors that need to be turned on and / or the load ratio based on the output MV;

[0047] The evaporation superheat of the main heat exchanger is controlled to be at a preset value by controlling the opening of the refrigeration expansion valve.

[0048] In a specific implementation process, the evaporation superheat SH20 of the main heat exchanger is equal to T20-Te1, where T20 is the outlet pipe temperature of the main heat exchanger, and Te1 is the saturation temperature corresponding to the suction main pipe pressure P10. The method for adjusting the opening of the refrigeration expansion valve is similar to the method for adjusting the opening of the electronic expansion valve.

[0049] The present invention also provides a defrost control method, comprising the following steps:

[0050] Determine whether the air heat exchanger is frosted based on the comprehensive heat exchange effect of the air heat exchanger;

[0051] Identify frosted air heat exchangers based on the opening of the electronic expansion valve and / or the outlet side temperature Ts of the air heat exchanger surface;

[0052] Select no more than half of the air heat exchangers that are identified as frosted and switch the heating circuit to the defrost branch;

[0053] The air heat exchanger switches to the heating circuit after defrosting is completed.

[0054] By adopting the above scheme, whether frosting occurs can be determined based on the comprehensive heat exchange performance of the air heat exchanger. At the same time, it is possible to determine which heat exchanger is frosted based on the principle that the opening of the electronic valve reflects the heat exchange performance of the air heat exchanger. The heat pump system of the above air-conditioning equipment can be used for heating and defrosting, and the conversion can be carried out according to the conditions.

[0055] Furthermore, the determining whether the air heat exchanger is frosted based on the comprehensive heat exchange effect of the air heat exchanger comprises the following steps:

[0056] Receiving the ambient air temperature T0 and the suction main pressure P10 outside the air heat exchanger;

[0057] Calculate the comprehensive heat transfer coefficient k of the air heat exchanger, k = V*P10 / (T0–Te1), where V is the actual load of the current compressor and Te1 is the saturation temperature corresponding to the pressure P10 of the suction main pipe (26);

[0058] Determine whether k is lower than a threshold value Kset. If so, determine that the air heat exchanger is frosted.

[0059] In the specific implementation process, for example, the air-conditioning equipment heat pump system includes two heat exchange units, that is, the defrost one-way valve includes a first one-way valve and a second one-way valve, the electronic expansion valve includes a first expansion valve and a second expansion valve, the air heat exchanger includes a first heat exchanger and a second heat exchanger, the electromagnetic three-way valve includes a first three-way valve and a second three-way valve, and the heating electromagnetic valve includes a first electromagnetic valve and a second electromagnetic valve; during the heating process, each of the air heat exchangers is in the heating circuit; when the first heat exchanger is defrosted, the first heat exchanger uses the defrost branch, that is, the first expansion valve and the first electromagnetic valve are closed, and the first three-way valve is connected to the first heat exchanger. A heat exchanger and a compressor exhaust port. The working compressor in the defrost branch extracts gaseous refrigerant from the suction main pipe. After compression and discharge, it is condensed and liquefied through the first heat exchanger, releasing heat and flowing into the liquid reservoir. At this time, the second heat exchanger is in the heating circuit, that is, the second expansion valve, the second solenoid valve, and the working compressor are open. The second three-way valve connects the second heat exchanger and the suction main pipe. The working compressor extracts gaseous refrigerant from the suction main pipe, which is condensed and liquefied through the main heat exchanger, releasing heat and flowing into the liquid reservoir. The liquid refrigerant in the liquid reservoir enters the second heat exchanger after passing through the second expansion valve, evaporating and absorbing heat, and then flows into the suction main pipe. Te1 can be obtained by table lookup. P10 is the suction main pipe pressure, that is, the compressor suction pressure. The total heat exchange Q is proportional to V*P1. Under a specific ambient temperature T0, a clean heat exchanger surface can achieve the highest k value. As the heat exchanger surface is covered with frost, the heat exchange capacity deteriorates. Due to the reduction in refrigerant evaporation, the compressor suction pressure P10 decreases, and the corresponding saturated evaporation temperature Te1 also decreases, which together drive the k value to decrease.

[0060] By adopting the above scheme, the k value is used to quantify the heat transfer performance of the air heat exchanger, the frosting of the air heat exchanger is detected in time, and the heat of the gaseous refrigerant is used to defrost it.

[0061] Furthermore, the threshold value Kset=KP*KM, wherein KP is a set frost degree threshold ratio, and KM is a maximum value of k of the air heat exchanger.

[0062] With the above solution, the KM can dynamically calculate the maximum k value under different outdoor temperatures T0 and manually set KP. For example, when KP is 70%, it is considered that when the heat exchange effect of the air heat exchanger drops below 70%, the air heat exchanger is frosted, and the frosting affects normal heating, requiring defrosting.

[0063] Furthermore, the method of identifying a frosted air heat exchanger based on the opening of the electronic expansion valve and / or the outlet side temperature Ts of the air heat exchanger surface includes the following steps:

[0064] Receive the outlet side temperature Ts of each air heat exchanger surface;

[0065] Determine whether Ts is lower than 0°C. If so, determine that the air heat exchanger is frosted.

[0066] By adopting the above solution, whether the air heat exchanger is frosted can be more accurately determined based on the temperature at the air outlet side.

[0067] Furthermore, the method of determining a frosted air heat exchanger based on the opening of the electronic expansion valve and / or the outlet side temperature Ts of the air heat exchanger surface includes the following steps:

[0068] It is determined whether the difference between the opening of a certain electronic expansion valve and the opening of other electronic expansion valves is lower than a threshold value. If so, it is determined that the air heat exchanger connected in series with the electronic expansion valve is frosted.

[0069] Furthermore, the defrost control method comprises the following steps:

[0070] Among the air heat exchangers judged to be frosted, the air heat exchanger with the most severe frosting is selected for defrosting.

[0071] When the opening degree of the electronic expansion valve connected in series is the smallest, or when the outlet side temperature Ts of the air heat exchanger surface is the smallest, it is considered that the frosting of the air heat exchanger is the most serious.

[0072] By adopting the above solution, only one unit with the most severe frosting is selected for defrosting, which minimizes the impact on the overall heating, determines the priority, and restores the overall heating efficiency more quickly.

[0073] In summary, the present invention has the following beneficial effects:

[0074] 1. The defrost branch extracts gaseous refrigerant from the suction main pipe, causing it to release heat and condense in the air heat exchanger, thereby achieving defrosting. There are at least two sets of heat exchange units, and the heating circuit can be kept running while the defrost branch is turned on. In this way, the heat absorbed from the outdoor air can be used to defrost the frosted air heat exchanger outdoors while heating is uninterrupted.

[0075] 2. Utilize the precise temperature control algorithm PID, and through the coordination of the electronic expansion valve and the working compressor, achieve the best energy efficiency of the working compressor, so that the system can operate under non-full load conditions for a long time;

[0076] 3. In addition to maximizing the suction pressure and the energy efficiency of the working compressor, the heat pump system for air conditioning equipment can also ensure the evaporation area of ​​multiple air heat exchangers, achieve a minimum air heat exchange temperature difference in the air heat exchangers, and maintain a high surface temperature of the air heat exchangers, effectively reducing the frosting rate and the number of defrost cycles. It can even prevent frosting when the surface temperature is higher than the ambient dew point temperature.

[0077] 4. The suction main pipe collects gaseous refrigerant, and the defrost branch extracts heat from the suction main pipe instead of the heat from the user's water circulation system, which has no significant impact on the temperature control on the user side and ensures normal heating operation. The refrigerant in the suction main pipe is extracted and compressed by the working compressor of at least one heating circuit. Even if one of the working compressors fails, the system can still operate normally. Except for the air heat exchanger being defrosted, all air heat exchangers participate in evaporation and heat absorption, ensuring the maximum evaporation area, ensuring efficiency and improving fault tolerance. At the same time, it maximizes the absorption of heat energy from the ambient air and ensures rapid defrosting.

[0078] 5. The defrost control method determines whether frost has formed based on the heat exchange performance of the air heat exchanger. Based on the principle that the opening of the electronic valve reflects the heat exchange performance of the air heat exchanger, the difference in the degree of frost of each air heat exchanger is determined. A targeted intelligent defrost algorithm is used to maximize the defrost energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0080] Figure 1 A schematic diagram of an embodiment of a heat pump system for air conditioning equipment according to the present invention;

[0081] Figure 2 A schematic diagram of the heating process of an embodiment of a heat pump system for air conditioning equipment of the present invention;

[0082] Figure 3 This is a schematic diagram of the defrosting process of an embodiment of a heat pump system for air conditioning equipment of the present invention;

[0083] Figure 4 A schematic diagram of another embodiment of a heat pump system for air conditioning equipment according to the present invention;

[0084] Figure 5 A schematic diagram of the refrigeration process of another embodiment of the heat pump system for air conditioning equipment of the present invention;

[0085] Figure 6 A schematic diagram of an embodiment of the heating control method of the present invention;

[0086] Figure 7 A schematic diagram of an embodiment of the refrigeration control method of the present invention;

[0087] Figure 8 A schematic diagram of an embodiment of the defrost control method of the present invention;

[0088] Figure 9 Schematic diagram of another embodiment of the defrost control method of the present invention;

[0089] Figure 10 This is a schematic diagram of another embodiment of the defrost control method of the present invention.

[0090] Description of Reference Numerals

[0091] Through the above description of the accompanying drawings, combined with the embodiments of the present invention, the technical solutions of the present invention can be more clearly understood and explained.

[0092] 11. Main heat exchanger; 12. Water circulation pump; 13. Water pipe; 14. Water outlet pipe; 21. Liquid reservoir; 22. Defrosting one-way valve; 221. First one-way valve; 222. Second one-way valve; 23. Electronic expansion valve; 231. First expansion valve; 232. Second expansion valve; 24. Air heat exchanger; 241. First heat exchanger; 242. Second heat exchanger; 25. Solenoid three-way valve; 251. First three-way valve; 252. Second three-way valve; 26. Intake main pipe; 27. Working compressor; 28. Working one-way valve; 29. ​​Heating solenoid valve; 291. First solenoid valve; 292. Second solenoid valve; 31. Auxiliary compressor; 32. Auxiliary one-way valve; 41. Refrigeration one-way valve; 42. Refrigeration expansion valve; 43. Refrigeration solenoid valve. DETAILED DESCRIPTION

[0093] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, like numbers in different figures represent like or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0094] The terms used in this invention are for the purpose of describing specific embodiments only and are not intended to limit the invention. The singular forms "a," "the," and "the" used in this invention and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0095] The present invention will be described in detail below through examples.

[0096] refer to Figure 1 The present invention provides an air conditioning equipment heat pump system, including a main heat exchanger 11, a water pipe 13 and a water outlet pipe 14 are provided on one side of the main heat exchanger 11, a water circulation pump 12 is provided on the water pipe 13, the air conditioning equipment heat pump system also includes a liquid reservoir 21, an air intake manifold 26 and at least two sets of heat exchange units, the heat exchange units include an electronic expansion valve 23, an air heat exchanger 24, an electromagnetic three-way valve 25, a working compressor 27, a working one-way valve 28 and a heating electromagnetic valve 29, the other side of the main heat exchanger 11 is connected to the liquid reservoir 21 in sequence through pipelines. , an electronic expansion valve 23, an air heat exchanger 24, an electromagnetic three-way valve 25, an air intake main pipe 26, a working compressor 27, a working one-way valve 28, and a heating solenoid valve 29 form a heating circuit. The electronic expansion valve 23 is provided with a defrost one-way valve 22 in parallel. The third end of the electromagnetic three-way valve 25 is connected to the pipeline between the working one-way valve 28 and the heating solenoid valve 29. The air intake main pipe 26, the working compressor 27, the working one-way valve 28, the electromagnetic three-way valve 25, the air heat exchanger 24, the defrost one-way valve 22, and the liquid reservoir 21 are connected through pipelines to form a defrost branch.

[0097] Among them, when using the heating circuit, the electronic expansion valve 23, the heating solenoid valve 29, and the working compressor 27 are opened, and the electromagnetic three-way valve 25 connects the air heat exchanger 24 and the intake main pipe 26; when using the defrost branch, the electronic expansion valve 23 and the heating solenoid valve 29 are closed, and in the defrost branch, the working compressor 27 extracts the gaseous refrigerant from the intake main pipe 26, condenses and liquefies through the air heat exchanger 24, and flows into the liquid reservoir 21.

[0098] Using the above solution, if Figure 2As shown, there are at least two groups of heat exchange units, and the air-conditioning equipment heat pump system may include two heat exchange units, namely, the defrost one-way valve 22 includes a first one-way valve 221 and a second one-way valve 222, the electronic expansion valve 23 includes a first expansion valve 231 and a second expansion valve 232, the air heat exchanger 24 includes a first heat exchanger 241 and a second heat exchanger 242, the electromagnetic three-way valve 25 includes a first three-way valve 251 and a second three-way valve 252, and the heating solenoid valve 29 includes a first solenoid valve 291 and a second solenoid valve 292; in the heating circuit, the working compressor 27 promotes the flow of refrigerant in the pipeline, the liquid refrigerant evaporates and absorbs heat in the air heat exchanger 24, and the gaseous refrigerant condenses and releases heat in the main heat exchanger 11, and exchanges heat with the water flow on the other side in reverse, and transfers heat to the water in the water outlet pipe 14, and a water tank and other heat exchangers can be connected between the water outlet pipe 14 and the water pipe 13 to achieve indoor heating using other heat exchangers.

[0099] like Figure 3 As shown, when the first heat exchanger 241 is defrosted, the first heat exchanger 241 uses the defrost branch, that is, the first expansion valve 231 and the first solenoid valve 291 are closed, the first three-way valve 251 connects the working check valve 28 and the first heat exchanger 241, and the working compressor 27 in the defrost branch extracts the gaseous refrigerant from the suction main pipe 26, condenses and liquefies through the first heat exchanger 241 to release heat and flows into the liquid reservoir 21; at this time, the second heat exchanger 242 is in the heating circuit, that is, the second expansion valve 232, the second solenoid valve 292, the working compressor 27 are closed, and the working compressor 27 is closed. The machine 27 is turned on, and the second three-way valve 252 connects the second heat exchanger 242 with the intake main pipe 26. The working compressor 27 extracts the gaseous refrigerant from the intake main pipe 26, which is condensed and liquefied by the main heat exchanger 11 to release heat. The liquid refrigerant flows into the liquid reservoir 21, and then evaporates and absorbs heat by the second heat exchanger 242 before flowing into the intake main pipe 26. The defrost branch can be opened while ensuring that the heating circuit is running, so that the heat absorbed from the outdoor air can be used to defrost the frosted air heat exchanger 24 outdoors under uninterrupted heating conditions.

[0100] The application utilizes the precise temperature control algorithm PID, realizes the best energy efficiency of the working compressor 27 by the cooperation of the opening degree of the electronic expansion valve 23 and the opening number of the working compressor 27, makes the system run in the non-full load working condition for a long time, can not only improve the suction pressure to the extreme and maximize the energy efficiency of the working compressor 27, but also can ensure the evaporation area of the multiple air heat exchangers 24, realize the minimum air heat exchange temperature difference of the air heat exchanger 24, that is, the surface temperature of the air heat exchanger is kept at a high level, effectively reduces the frosting speed and the defrosting frequency, and even when the surface temperature is higher than the ambient dew point temperature, the frosting phenomenon is avoided; the suction main pipe 26 collects the gaseous refrigerant, the defrosting branch extracts the heat of the suction main pipe 26, rather than the heat of the user water circulation system, has no significant influence on the user side temperature control, and ensures the normal heating work; the working compressor 27 of at least one heating circuit extracts the refrigerant of the suction main pipe 26 and compresses, and when one of the working compressors 27 fails, the system can also run normally, ensures that the refrigerant passes through all the air heat exchangers 24, ensures the maximum evaporation area and the efficiency ratio, and improves the fault tolerance rate; the working check valve 28 prevents the gaseous refrigerant from flowing back into the working compressor 27 and causing damage to the working compressor 27.

[0101] In a preferred embodiment of the application, the main heat exchanger 11 can be a plate heat exchanger, a shell-and-tube heat exchanger or a double-pipe heat exchanger.

[0102] In a preferred embodiment of the application, at least one of the working compressors 27 is a variable capacity compressor.

[0103] In a preferred embodiment of the application, at least one of the working compressors 27 is a digital scroll compressor.

[0104] By adopting the above scheme, the variable capacity compressor can adopt frequency conversion technology, a multi-stage control system, digital scroll technology and the like to realize accurate adjustment of the overall heating / cooling capacity.

[0105] Reference Figure 4 In a preferred embodiment of the application, an auxiliary compressor 31 and an auxiliary check valve 32 are further connected between the suction main pipe 26 and the main heat exchanger 11, and the auxiliary compressor 31 is a variable capacity compressor.

[0106] By adopting the above scheme, the auxiliary check valve 32 prevents the gaseous refrigerant from flowing back into the auxiliary compressor 31, and the auxiliary compressor 31 adjusts the total heating capacity by using the variable capacity technology.

[0107] In a preferred embodiment of the application, the heat exchange unit is provided in four groups.

[0108] With the above solution, when one defrost branch is selected for defrosting, the other three heating circuits can ensure a better heating effect and the compressor has better efficiency.

[0109] refer to Figure 5 In a preferred embodiment of the present invention, a refrigeration one-way valve 41 is connected to the pipeline between the main heat exchanger 11 and the liquid reservoir 21, the liquid reservoir 21 is connected to the other end of the main heat exchanger 11 through a pipeline, and a refrigeration solenoid valve 43 is provided in the pipeline. A branch is formed between the refrigeration one-way valve 41 and the pipeline of the main heat exchanger 11, the branch is connected to the intake main pipe 26, and a refrigeration solenoid valve 43 is provided on the branch.

[0110] Among them, when the refrigeration solenoid valve 43 and the electromagnetic three-way valve 25 are opened, the heating solenoid valve 29 and the electronic expansion valve 23 are closed, the main heat exchanger 11, the refrigeration solenoid valve 43, the intake manifold 26, the working compressor 27, the working one-way valve 28, the electromagnetic three-way valve 25, the air heat exchanger 24, the defrost one-way valve 22, the liquid reservoir 21, and the refrigeration expansion valve 42 are connected in sequence to form a refrigeration circuit, so that the refrigerant flows in the opposite direction and evaporates and absorbs heat in the main heat exchanger 11; the refrigeration one-way valve 41 is used to prevent the refrigerant from flowing back to the main heat exchanger 11, the electromagnetic three-way valve 25 connects the working one-way valve 28 and the air heat exchanger 24, and the refrigeration expansion valve 42 cooperates with the working compressor 27 to adjust the cooling capacity.

[0111] By adopting the above scheme, the heat pump system of the air-conditioning equipment changes the flow direction of the refrigerant by switching the electromagnetic three-way valve 25, the heating electromagnetic valve 29, the electronic expansion valve 23, the cooling expansion valve 42, and the heating electromagnetic valve 29, thereby providing a heating function while also being able to cool, thereby achieving dual cooling and heating effects.

[0112] In a preferred embodiment of the present invention, a heat exchange fan is provided opposite to the air heat exchanger 24 .

[0113] By adopting the above solution, the heat exchange fan accelerates the air flow on the surface of the air heat exchanger 24, thereby improving the heat exchange rate.

[0114] In a preferred embodiment of the present invention, the air-conditioning equipment heat pump system also includes a control system, which includes a main controller and a first temperature sensor, a second temperature sensor, a third temperature sensor and a first pressure sensor electrically connected thereto, the first temperature sensor being used to measure the water pipe 13 temperature T01, the second temperature sensor being used to measure the air heat exchanger 24 pipeline outlet temperature T21, the third temperature sensor being used to measure the air outlet side temperature Ts on the surface of the air heat exchanger 24, and the first pressure sensor being used to measure the intake manifold 26 pressure P10, wherein Ts refers to the air outlet temperature of the air heat exchanger 24, and T21 refers to the refrigerant temperature in the refrigerant outlet direction pipeline of the air heat exchanger 24.

[0115] By adopting the above solution, the temperature and pressure parameters required in the heating circuit and the defrost circuit are obtained, which facilitates defrost control in the heating circuit.

[0116] In a preferred embodiment of the present invention, the main controller is further electrically connected to a fourth temperature sensor, and the fourth temperature sensor is used to measure the outlet pipe temperature T20 of the main heat exchanger 11.

[0117] The above technical solution is adopted to facilitate the measurement of data in the refrigeration circuit and facilitate refrigeration control.

[0118] In a preferred embodiment of the present invention, the main controller is further electrically connected to a fifth temperature sensor and a sixth temperature sensor. The fifth temperature sensor measures the outdoor air temperature T0, and the sixth temperature sensor is used to measure the temperature of the water outlet pipe 14.

[0119] The above solution makes it easier to obtain the cooling or heating capacity obtained by the user side, so as to adjust the temperature more accurately and detect faults in time.

[0120] In a preferred embodiment of the present invention, the main controller is also electrically connected to a seventh temperature sensor, a second pressure sensor, and a third pressure sensor. The seventh temperature sensor is used to measure the temperature of the intake manifold 26, the second pressure sensor is used to measure the exhaust pressure of the working compressor 27, and the third pressure sensor is used to measure the exhaust pressure of the auxiliary compressor 31.

[0121] The above solution makes it easy to obtain various data so as to better evaluate and control the performance of the compressor.

[0122] In a preferred embodiment of the present invention, the present invention provides an air-conditioning device on the other hand, which includes the air-conditioning device heat pump system as described above. Since the air-conditioning device heat pump system has the above-mentioned technical effects, the air-conditioning device should also have corresponding technical effects.

[0123] refer to Figure 6 In a preferred embodiment of the present invention, the present invention provides a heating control method, comprising the following steps:

[0124] S101. Connect the heating circuit and close other paths;

[0125] S102. Get the water pipe temperature T01 and the user set temperature Tset, calculate the temperature difference dT = T01-Tset, and use the PID algorithm to calculate the output MV = PID (dT);

[0126] S103. Calculate the number of compressors that need to be turned on and / or the load ratio based on the output MV;

[0127] S104 . Control the evaporation superheat of the air heat exchanger 24 to a preset value by controlling the opening of the electronic expansion valve 23 .

[0128] In the specific implementation process, the output volume MV is generally limited to the range of 5 to 100 (%). The number of compressors that need to be turned on can be converted according to the PID output volume MV. The compressors may include a working compressor 27 or a working compressor 27 and an auxiliary compressor 31. For example, if four working compressors 27 are included, all of which are fixed capacity and each compressor accounts for 25%, the output volume MV is 50%, which means that two working compressors 27 are turned on. When variable capacity compressors are included, the loading ratio of the variable capacity compressors can be refined. For example, if there are a total of four working compressors 27, three of which are fixed capacity and the other is variable capacity, the output volume MV is 50%, which means that two working compressors 27 are turned on. If the output MV is 60%, two fixed-capacity compressors (25%*2) can be turned on, and then the variable-capacity compressor can be turned on 40% (25%*40%). The total output MV = 25%*2+25%*40% = 60%. For example, there are a total of 4 compressors, including 3 working compressors 27, all of which are fixed-capacity, and 1 auxiliary compressor 31, which is variable-capacity. If the output MV is 60%, two working compressors 27 (25%*2) can be turned on, and then the auxiliary compressor 31 can be turned on 40%; if the temperature deviation dT<-2°C, the heating operation will be stopped until the temperature deviation dT>2°C and then restarted.

[0129] By adopting the above solution, by adjusting the cooling capacity output appropriately rather than at its maximum, the evaporation temperature is made the highest within the working range, thereby obtaining the maximum energy efficiency ratio of the compressor, while at the same time achieving the highest surface temperature of the air heat exchanger and thus minimizing frost.

[0130] In a preferred embodiment of the present invention, the step S104 of controlling the evaporation superheat of the air heat exchanger 24 to a preset value by controlling the opening of the electronic expansion valve 23 comprises the following steps:

[0131] Receive the outlet temperature T21 of the air heat exchanger 24 and the pressure P10 of the air intake manifold 26;

[0132] Calculate the evaporation superheat SH1 of the air heat exchanger 24 = T21 - Te1, where Te1 is the saturation temperature corresponding to the pressure P10 of the suction main pipe 26;

[0133] If it is determined that the evaporation superheat SH1 exceeds the preset value, the opening V21 of the electronic expansion valve 23 is increased and adjusted; if SH1 is lower than the preset value, the opening V21 of the electronic expansion valve 23 is decreased and adjusted.

[0134] In the specific implementation process, Te1 can be obtained by looking up the table method. The preset value of SH1 is usually around 5°C. The opening of the electronic expansion valve 23 is V21=V*(1+dV1), where V is the actual load of the current compressor, dV1 is the set adjustment amount, the initial value is 0, and it can vary within the range of ±50%. When SH1 is too high, dV1 is appropriately increased. When SH1 is too small, dV1 is appropriately reduced. The judgment period can be set to about 3 to 5 seconds, and the single adjustment amount of dV1 can be set to about 2%.

[0135] refer to Figure 7 The present invention provides a refrigeration control method, comprising the following steps:

[0136] S201. Connect the refrigeration circuit and close other paths;

[0137] S202 receives the water pipe temperature T01 and the user set temperature Tset, calculates the temperature difference dT = T01-Tset, and uses the PID algorithm to calculate the output MV = PID (dT);

[0138] S203. Calculate the number of compressors that need to be turned on and / or the load ratio based on the output MV;

[0139] S204 . Control the evaporation superheat of the main heat exchanger 11 to a preset value by controlling the opening of the refrigeration expansion valve 42 .

[0140] In a specific implementation process, the evaporation superheat SH20 of the main heat exchanger 11 is SH20 = T20 - Te1, where T20 is the outlet pipe temperature of the main heat exchanger 11, and Te1 is the saturation temperature corresponding to the pressure P10 of the suction main pipe (26). The method for adjusting the opening of the refrigeration expansion valve 42 is similar to the method for adjusting the opening of the electronic expansion valve 23.

[0141] refer to Figure 8 The present invention also provides a defrosting control method, comprising the following steps:

[0142] S310. Determine whether the air heat exchanger 24 is frosted based on the comprehensive heat exchange effect of the air heat exchanger 24;

[0143] S320. Identify the frosted air heat exchanger 24 based on the opening of the electronic expansion valve 23 and / or the outlet side temperature Ts of the air heat exchanger 24;

[0144] S330. Select no more than half of the air heat exchangers 24 that are determined to be frosted and switch the heating circuit to the defrost branch;

[0145] S340. The air heat exchanger 24 is switched to a heating circuit after defrosting is completed.

[0146] By adopting the above scheme, whether frosting occurs can be determined based on the comprehensive heat exchange performance of the air heat exchanger. The principle that the opening of the electronic valve reflects the heat exchange performance of the air heat exchanger and the surface air outlet temperature TS can be used to determine which heat exchanger is frosted. The heat pump system of the air conditioning equipment can be used for heating and defrosting, and the conversion can be carried out according to the conditions.

[0147] refer to Figure 9 In a preferred embodiment of the present invention, the step S310 of determining whether the air heat exchanger 24 is frosted based on the comprehensive heat exchange effect of the air heat exchanger 24 comprises the following steps:

[0148] S311 receives the air temperature T0 outside the air heat exchanger 24 and the suction manifold pressure P10 26;

[0149] S312. Calculate the overall comprehensive heat transfer coefficient k of the air heat exchanger 24, k = V*P10 / (T0–Te1), where V is the actual load of the current compressor, and Te1 is the saturation temperature corresponding to the pressure P10 of the suction main pipe 26; for example, when the PID algorithm determines that the output MV provided by the compressor system that needs to be rectified is 70%, and the actual situation is that only three of the four compressors with the same fixed capacity are turned on, the actual load V is 75%.

[0150] S313. Determine whether k is lower than the threshold value Kset. If so, S314. Determine whether the air heat exchanger 24 is frosted.

[0151] In practice, Te1 can be obtained by looking up a table. P10 is the suction manifold 26 pressure, or the compressor suction pressure. The total heat exchange capacity, Q, is proportional to V*P1. At a specific ambient temperature, T0, a clean heat exchanger surface achieves the highest k value. As the heat exchanger surface becomes covered with frost, heat transfer capacity deteriorates. Due to reduced refrigerant evaporation, the compressor suction pressure, P10, decreases, and the corresponding saturated evaporation temperature, Te1, also decreases, both driving the k value downward.

[0152] By adopting the above scheme, the k value is used to quantify the heat exchange performance of the air heat exchanger 24, and the frosting of the air heat exchanger 24 is discovered in time, and the heat of the gaseous refrigerant is used to defrost it.

[0153] In a preferred embodiment of the present invention, the threshold value Kset=KP*KM, wherein KP is a set frost degree threshold ratio, and KM is the maximum value of k of the air heat exchanger 24 .

[0154] Using the above solution, the KM can dynamically record the maximum k value at different outdoor temperatures T0 and manually set the KP. For example, when the KP is 70%, it is considered that when the heat exchange efficiency of the air heat exchanger 24 drops below 70%, the air heat exchanger 24 is frosted, and this frosting affects normal heating, requiring defrosting. In a preferred embodiment of the present invention, the step S320 of determining a frosted air heat exchanger 24 based on the opening of the electronic expansion valve 23 and / or the outlet side temperature Ts of the air heat exchanger 24 includes the following steps:

[0155] S321 receives the outlet side temperature Ts of each air heat exchanger 24;

[0156] S322. Determine whether Ts is lower than 0°C. If so, S323. Determine whether the air heat exchanger 24 is frosted.

[0157] By adopting the above solution, whether the air heat exchanger 24 is frosted can be accurately determined based on the temperature at the air outlet side.

[0158] refer to Figure 10 In a preferred embodiment of the present invention, the step S320 of determining the frosted air heat exchanger 24 based on the opening of the electronic expansion valve 23 and / or the outlet side temperature Ts of the air heat exchanger 24 comprises the following steps:

[0159] S324. Determine whether the difference between the opening of a particular electronic expansion valve 23 and the openings of the other electronic expansion valves 23 is below a threshold. If so, S325. Determine whether the air heat exchanger 24 connected in series with the electronic expansion valve 23 is frosted. For example, if the opening of a particular electronic expansion valve 23 is 50%, and the openings of the other electronic expansion valves 23 are 58%, 65%, and 63%, and the preset threshold is -10%, then if any difference (50% - 65% = -15%) exceeds -10%, the air heat exchanger 24 connected in series with the electronic expansion valve 23 is considered severely frosted. The severity of frost is ranked in ascending order of opening.

[0160] During the specific implementation process, the surface outlet side temperature Ts of the air heat exchanger 24 and the opening of the electronic expansion valve 23 can be judged at the same time to determine whether the surface outlet side temperature Ts of a certain air heat exchanger 24 is lower than 0°C and whether the difference between the opening of the electronic expansion valve 23 connected in series with it and the opening of other electronic expansion valves 23 is lower than the threshold. If so, it is determined that the air heat exchanger 24 is frosted.

[0161] In a preferred embodiment of the present invention, the defrost control method comprises the following steps:

[0162] S331. Among the air heat exchangers 24 that are judged to be frosted, the air heat exchanger 24 with the most severe frosting is selected for defrosting. The most severe frosting is when the opening of the corresponding electronic expansion valve 23 is the smallest or the surface air outlet side temperature Ts is the lowest.

[0163] This solution selects only the most severely frosted unit for defrosting, minimizing the impact on overall heating, prioritizing the unit, and rapidly restoring overall heating efficiency. Assuming the superheat control target for each air heat exchanger is the same (approximately 5°C), the air heat exchanger with the smallest opening of its corresponding electronic expansion valve (23) will be the most severely frosted. The air heat exchanger (24) with the lowest outlet temperature (Ts) will also be the most severely frosted.

[0164] In a preferred embodiment of the present invention, the defrost control method comprises the following steps:

[0165] During the defrosting process, it is determined whether the ambient air temperature T0 and the air heat exchanger surface temperature Ts are both above 0°C. If so, the heat exchange fan is started; if not, the heat exchange fan is turned off.

[0166] By adopting the above solution, the heat exchange fan is turned off to concentrate the temperature on defrosting during the defrosting process, and the heat exchange fan is turned on to blow away the melted water on the surface of the air heat exchanger during the defrosting process.

[0167] It should be pointed out that for ordinary technicians in this field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A heat pump system for air conditioning equipment, characterized in that: The heat pump system comprises a main heat exchanger (11), a water pipe (13) and a water outlet pipe (14) are provided on one side of the main heat exchanger (11), a water circulation pump (12) is provided on the water pipe (13), and the heat pump system of the air-conditioning equipment further comprises a liquid reservoir (21), an air intake manifold (26) and at least two sets of heat exchange units, wherein the heat exchange units comprise an electronic expansion valve (23), an air heat exchanger (24), an electromagnetic three-way valve (25), a working compressor (27), a working one-way valve (28) and a heating electromagnetic valve (29); The other side of the main heat exchanger (11) is connected in sequence to a liquid reservoir (21), an electronic expansion valve (23), an air heat exchanger (24), an electromagnetic three-way valve (25), an air intake manifold (26), a working compressor (27), a working one-way valve (28), and a heating electromagnetic valve (29) through pipelines, forming a heating circuit; The electronic expansion valve (23) is provided with a defrosting one-way valve (22) in parallel, and the third end of the electromagnetic three-way valve (25) is connected to the pipeline between the working one-way valve (28) and the heating electromagnetic valve (29); The air intake main pipe (26), the working compressor (27), the working one-way valve (28), the electromagnetic three-way valve (25), the air heat exchanger (24), the defrost one-way valve (22), and the liquid reservoir (21) are connected through pipelines to form a defrost branch circuit; The connecting pipes after the exhaust ports of the working compressors (27) form a high-pressure side structure that operates independently of each other, and the working compressors (27) of each high-pressure side heat exchange unit do not share a common exhaust pipe; the connecting pipes before the intake ports of the working compressors (27) form a parallel low-pressure side structure through the intake main pipe (26); When any heat exchange unit switches to the defrost branch, its corresponding working compressor (27) maintains operation, and the high-pressure refrigerant flows into the air heat exchanger (24) through the third end of the electromagnetic three-way valve (25) of the heat exchange unit for defrosting, and the high-pressure side of the remaining heat exchange units continues to maintain the high-pressure state of the heating circuit, and the refrigerant flow of the defrost branch is driven by the exhaust pressure of the corresponding working compressor (27); An auxiliary compressor (31) and an auxiliary check valve (32) are further connected between the air intake manifold (26) and the main heat exchanger (11), wherein the auxiliary compressor (31) is a variable capacity compressor; A refrigeration one-way valve (41) is connected to the pipeline between the main heat exchanger (11) and the liquid reservoir (21), the liquid reservoir (21) is connected to the other end of the main heat exchanger (11) through a pipeline, and a refrigeration expansion valve (42) is provided in the pipeline. A branch is formed between the refrigeration one-way valve (41) and the pipeline of the main heat exchanger (11), the branch is connected to the air intake main pipe (26), and a refrigeration solenoid valve (43) is provided on the branch.

2. An air conditioning device, characterized in that: The air conditioning device comprises the air conditioning device heat pump system according to claim 1 .

3. A defrost control method, characterized in that: The heat pump system for air conditioning equipment as claimed in claim 1 comprises the following steps: determining whether the air heat exchanger (24) is frosted based on the comprehensive heat exchange effect of the air heat exchanger (24); identifying the frosted air heat exchanger (24) based on the opening of the electronic expansion valve (23) and / or the air outlet side temperature Ts of the air heat exchanger (24); selecting no more than half of the air heat exchangers (24) that are frosted and are located and switching them to the defrost branch; and switching the air heat exchanger (24) to the heating circuit after defrosting is completed.

4. The defrost control method according to claim 3, wherein: Determining whether the air heat exchanger (24) is frosted based on the comprehensive heat exchange effect of the air heat exchanger (24) includes the following steps: Receiving the ambient air temperature T0 outside the air heat exchanger (24) and the suction main pipe (26) pressure P10; Calculating the comprehensive heat transfer coefficient k of the air heat exchanger (24), k=V*P10 / (T0-Te1), where V is the actual load of the current compressor and Te1 is the saturation temperature corresponding to the pressure P10 of the suction main pipe (26); It is determined whether k is lower than a threshold value Kset. If so, it is determined that the air heat exchanger (24) is frosted.

5. The defrost control method according to claim 4, wherein: The threshold value Kset=KP*KM, wherein KP is a set frost degree threshold ratio, and KM is the maximum value of k of the air heat exchanger (24).

6. The defrost control method according to claim 4 or 5, characterized in that: The method of determining a frosted air heat exchanger (24) based on the opening degree of the electronic expansion valve (23) and / or the air outlet side temperature Ts of the air heat exchanger (24) surface comprises the following steps: receiving the air outlet side temperature Ts of each air heat exchanger (24); It is determined whether Ts is lower than 0°C. If so, it is determined that the air heat exchanger (24) is frosted.

7. The defrost control method according to claim 3, wherein: The method of determining a frosted air heat exchanger (24) based on the opening degree of the electronic expansion valve (23) and / or the air outlet side temperature Ts of the air heat exchanger (24) surface comprises the following steps: It is determined whether the difference between the opening of a certain electronic expansion valve (23) and the opening of other electronic expansion valves (23) is lower than a threshold value. If so, it is determined that the air heat exchanger (24) connected in series with the electronic expansion valve (23) is frosted.

8. The defrost control method according to claim 3, 4, 5 or 7, characterized in that: The defrost control method comprises the following steps: Among the air heat exchangers (24) judged to be frosted, the air heat exchanger (24) with the most severe frosting is selected for defrosting, wherein the most severe frosting is when the opening degree of the corresponding electronic expansion valve (23) is the smallest or the surface air outlet side temperature Ts is the lowest.

Images